Thank you very much for your continued support of back number.

Due to a server version upgrade,

We will be performing nighttime maintenance on the following dates.

During this period, access to the site and all services will be unavailable.

We sincerely apologize for any inconvenience this may cause our customers, and we appreciate your understanding and cooperation.

■ Maintenance period

Thursday, May 14, 2026 00:00 to Thursday, May 14, 2026 07:00

*Please note that maintenance times may vary.

■Target Services

back number official website

- Official fan club "one room"

We apologize for any inconvenience this may cause, and we appreciate your understanding.